Electric heater.



E. B E N N ETT.E

ELECTRIC HBA-IER.

(Application led Tf", 1899J;

l'llllll /NVE/VTOH aml M TTOHNEY.

v W/TNESSES VUNITED STATES PrrruNTy QFBICE. 'I

wEsmNeHousE, or PITTSBURG, PENNSYLVANIA# Application tied December 7,1899. seriarmsam. (Nqmtaeief:

^ L.To all whom it may concern:

Beit known that I, EDWARDKBENNETT, a

a citizen of the United States, residing at Jeannette, in the county ofWestmoreland and State of Pennsylvania, have invented a new and usefulImprovement in Electric Heaters,

(Case No. 852,) of which the following is a specification.

My invention relates to electric heaters, and has particular referenceto devices employed in connection with electric lamps of the class inwhich the glowers are non-conductors of electricity when cold, butbecome luminousconductors when heated to the proper temperature.

The object of my inventionv is to provide a heater for use in raisingthe lamp-glowers to a proper temperature which shall be simple andinexpensive in construction and effective in operation and one whichshall be less liable to injury in process of construction and in usethan the devices heretofore employed for performing the same function.

It has been proposed prior to 'my invention to wind the heater-wire in ahelical coil on the surface of a tube of insulating refractory materialand to fasten the ends of such wire to terminal wires of larger size.The means heretofore employed for fastening the terminal wires to thetube comprised notches cut in the tube near. its ends, the terminalwires being-wound about the tube in such notches and their free endstwisted together` It was found in practice that the notches'cut in thetube weakened it very materially and the twisting of the terminal wirestogether was liable to result in breaking either them or the tube orboth. The bending and twisting of the terminal wires also frequentlyloosened the heater-wire from the surface of the tube and left itexposed, so that it was fused by the first rush of current when theheater was put into use.

In order to avoid the difficulties and objections specifled above,l havedevised the heater shown in the accompanying drawings, in whichl Figurel is a side elevation of one forni of heater-tube, showing the terminalwires in position and the heater-wire before the outer ELECTRIC HEATER.

SPECIFICATION forming par@ of Letters Patent No. 652,504, dateat'unei12e',-'lato coating is applied. 1?`ig.f2,is,any endgeleyation of theheater shown inligfl'. 'Figsgfaand 4 are respectively a side and.attendueleyation of the form of heater shotynngFigsflfand 2 with theheater-wire covered andcuibodying4 a slightly-modified arrangemen-t'of,terminal wires. Figs. 5 and are' resptivelyaplan view and an endelevation of a heate'ryhaving the modified form oftube`-f` ReferringparticularlytoFigsl to t elusive, the tube l is moldedlfrq .talcum orother suitable insulating'refractory material and subsequently baked.iBefore being baked, however, holes"slightlylarger than the terminalwire to be employedlare' punched through the tube near each end." i Thetihli nal wires 2 are .threaded'througlr the'holes, and a small quantityof sui-table'paste -isfthen .applied to each hole around 'the' wire.-The tube is then baked until it becomes sufficiently hard for thepurpose for which it is to be elnployed. In the baking operation thepaste applied to the apertures becomes fused` and seals the terminalwires securely in position. The heater-Wire 3 is then wound about thetube l as a helical coil and its ends attached to the ends of theterminal Wires 2, project* ing from one side of the tube.

In case the heater is to be high-voltage circuit and the heater-wire isconsequently small in cross-section the ends of the wire may be attachedto thev terminal wires by wrapping them around the ends of the latter,as indicated in Figs. 2 and 4, and at the right hand in Figs. l and 3,after which theprojecting'ends of the terminal wires may be bent overagainst the surface of the tube, as' indicated at the left in Figs. 1and 3. In case the heater is to be employed in low-'voltage circuitscarrying relatively-large currents the heater-wire is fused to thelead-wire at the start, and at the completion of the winding it istwisted around the other leadwire and fused to it and then bent down tothe surface of the tube. is rendered necessary in order to avoid thedestruction of the heater-wire by' reason of the poor contact whichwould be made by merely twisting the same around the terminal Wire.

employed in a.

Thisl construction In case the tube is to be applied to a spindle ormandrel for the purpose of winding the the port-ion of the termi- A tionof the terminal and heater wires is also made in the same manner as thatalready described.

Whatever may be the form of the heater it will preferably be providedwith a coating 4 of -non conducting refractory material of sufficientthickness to cover and embed the heater-wire.

I desire it to be understood that the composition, size, and arrangementof the several parts of the heater may be varied from "what is shownwithout departing from my invention and that the heater is notnecessarily restricted to use in connection withwelectric lamps. r,

I' claim as my invention- 1. An electric heater comprising a tube ofinsulating,refractory material,terminal wires y projecting throughperforations adjacent to the ends of the tube and fused therein, and aheater-wire helically coiled around the tube and having its ends joinedto the terminal Wires, `Substantially as described.

2. An electric heater comprising a tube of insulating, refractorymaterial having apertures adjacent to its ends, terminal wiresprojecting through said apertures and fused therein, and a heater-wirehelically coiled around the tube and having each end joined to aprojecting end of a terminal Wire, substantially as described.

3. An electric heater for electric lamps of the. type describedcomprising a attened tube of insulating, refractory material' providedwith terminal wires projecting through and fused into openings in saidtube and having a coiled heater-Wire joined to the terminal wires,substantially as desc-ribed.

4. An electric heater comprising a tube of insulating, refractorymaterial of approximately-elliptical cross-section and having ap erturesadjacent to its ends, terminal wires projecting through and fused intosaid apertures, and a heater-wire coiled around the tube and joined at.its ends. to the terminal wire, substantially as described.

In testimony whereof l have hereunto subscribed my name this 5th day ofDecember, 1899.

ED\VARD BENNETT.

iVitnc-sscs:

H. A. (JRooKs, WESLEY G. CARR.

